As Public Advocate Bill de Blasio inches closer to Gracie Mansion, voters are tasked with deciding his replacement in a race largely overshadowed by the hubbub of the mayoral and comptroller elections.

"It's not a sexy thing," said university professor and candidate Catherine Guerriero. "The public advocate is simply the city's ombudsman."

Created in 1994 with a relatively small budget, the Office of the Public Advocate is fluid: The person at its helm largely determines its direction and role in New York City politics.

For the two leading candidates, Brooklyn Councilwoman Letitia "Tish" James and state Sen. Daniel Squadron, this flexibility gives them the opportunity to act as a voice for overlooked New Yorkers and issues important to them.

"I would like to look more at social justice issues in the city," James said, noting she'd like to make the office's $2.1 million budget independent from the mayor and City Council.

James said she also has council support to increase the office's budget if elected.

Squadron, who represents parts of lower Manhattan and Brooklyn, would divide the office into four bureaus: Most Vulnerable, Children's, Accountability and Housing.

"There's no question this office still needs to be built," Squadron said, calling his plan a "reimagination" of the office.

Reshma Saujani, founder of Girls Who Code, a nonprofit aimed at closing the gender gap in technology and engineering, said she wants to build on her experience as deputy public advocate, a role she served under de Blasio until March 2012.

In an email, Saujani said she would "restructure the office so that it plays a stronger role in improving public education, helping to create more jobs, expanding affordable housing, empowering immigrant entrepreneurs and enhancing the lives of women and girls across the five boroughs."

Guerriero, who teaches at NYU and Columbia, would create an Advocate Think Tank, employing graduate students who will publish research and reports on a variety of city issues.

"Instead of railing to the gods and [making] complaints, we can actually get things done," she said.

One of the key criticisms of the office is that it is merely a stepping-stone for politicians like de Blasio. In 2009, Mayor Michael Bloomberg said the public advocate was a "total waste of everybody's money."

This is a sentiment vehemently opposed by this year's candidates.

"In a big city like ours, a public advocate independent of special interests is a critical piece," Squadron said.

The office goes beyond advocacy: Whoever is elected would become interim mayor should anything happen to the city's new leader.